In this paper the scattering properties of an infinite grid of conducting strips in a multilayer structure is studied by a spectral domain technique. To calculate the scattered field we Fourier expand the induced currents on the strips and use the numerical algorithm GIDMULT to evaluate the spectral domain Green's functions. The results are compared with data obtained using the asymptotic strip boundary condition (ASBC). We have shown that the exact numerical results approach the ASBC results when the strip period decreases for all relative strip widths. This paper is done while Zvonimir Sipus was a Ph.D. Student at Chalmers University of Technology, Gothenburg, Sweden.